DETAILED CORRESPONDENCE
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Response to Amendment
Applicant’s amendment, filed 10/09/2025, has been entered. Claim 29 is amended. Claim 30 is new. Claim 26 is cancelled. Claims 12-25 and 27-30 are currently pending in this application.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-21, 23-25, and 27-28 are rejected under 35 U.S.C. 103 as being unpatentable over Yoshida (JP5269919B2, refer to enclosed translations within the 07/31/2024 office action for citations) in view of Mizuno (JP3503193B2, refer to enclosed translation for citations).
Regarding claim 12,
Yoshida teaches membrane-electrode assembly [0001] for a fuel cell [0001], the membrane-electrode assembly [0001] comprising:
an electrolyte membrane (Fig. 1, 4; [0016]),
a pair of catalyst layers (Fig. 1, cathode catalyst layer 3, anode catalyst layer 5; [0022]) stacked respectively on one and the other surfaces of the electrolyte membrane (Fig. 1, cathode catalyst layer 3, anode catalyst layer 5; [0022])
and a pair of gas diffusion layers stacked respectively on a side opposite to the electrolyte membrane of one of the pair of catalyst layers and on a side opposite to the electrolyte membrane of the other one of the pair of catalyst layers (Fig. 1, 2, 6; [0022]),
wherein one of the pair of catalyst layers contains catalyst particles A and a first conductive material (see [0016], “the catalyst layer contains conductive powder particles carrying a catalyst component and fibrous carbon”)
one of the pair of gas diffusion layers which is in contact with the one of the catalyst layers contains a second conductive material (see [0016] gas diffusion layer has a layer containing… a fibrous carbon”, wherein carbon is a conductive material),
the first conductive material includes a first particulate conductive member and a first fibrous conductive member (see [0016], “the catalyst layer contains conductive powder particles carrying a catalyst component and fibrous carbon”, wherein carbon is a conductive material),
the second conductive material includes at least a second fibrous conductive member (see [0016] gas diffusion layer has a layer containing… a fibrous carbon”, wherein carbon is a conductive material),
a content K2 by mass of the second fibrous conductive member in the second conductive material ([0018], “and the vapor grown carbon fiber content is 1 to 95% by mass of the whole layer”, While Yoshida teaches at most 95% by mass of the whole layer compared to the claimed language involving just the total mass of conductive material, the ratio of the carbon fiber to just the mass of conductive material should be even higher than 1 to 95%).
and a content K1 by mass of the first fibrous conductive member in the first conductive material (see [0044] which describes mixing .1 to 30% by mass of fibrous carbon with the main component (i.e., the conductive particles and catalyst). While the precise value of K2 is not disclosed, as described above, it would be obvious to one of ordinary skill in the art before the effective filing date of the present invention that K2 is greater than 1 to 95%, which overlaps with and thus obviates the claimed range that the content K2 is larger than the content K1. Additionally, [0045] describes having too much mass mixed in with the catalyst layer (corresponding to K1) causes the battery characteristics to deteriorate, further underscoring why the mass percent range for K1 is significantly smaller, obviating the pursuit of K2>K1. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. (See MPEP 2144.05 I.)
Yoshida fails to teach the gas diffusion layer has a structure having no substrate layer. Mizuno teaches a gas diffusion layer without a substrate in the final product (see [0010], wherein the substrate is peeled off the final product). It would be obvious to one of ordinary skill in the art before the effective filing date of the present invention to assemble the gas diffusion member in the manner disclosed by Mizuno, wherein the particles and fibers are entangled [0010] and the substrate is peeled off in the final product [0010], such that the gas diffusion layer in contact with the one of the catalyst layers has a structure having no substrate layer, in order to improve gas diffusivity, as suggested by Mizuno [0010]. Additionally, the combination is obvious because Yoshida cites Mizuno as a method of forming a GDL without a substrate ([0014], Yoshida).
Regarding claim 13,
Yoshida in view of Mizuno teaches the membrane-electrode assembly according to claim 12 (see rejection of claim 12 above), wherein fiber length is generally preferred to be 50 μm or less [0062], such that Yoshida teaches wherein a ratio of a fiber length of the second fibrous conductive member to a fiber length of the first fibrous conductive member is 50 μm to 50 μm, or 1, which is within the claimed range of 0.5 to 2.0.
Regarding claim 14,
Yoshida in view of Mizuno teaches the membrane-electrode assembly according to claim 12 (see rejection of claim 12 above), wherein fiber diameter is generally preferred to be 1 μm or less [0026], such that Yoshida teaches wherein a ratio of a fiber diameter of the second fibrous conductive member to a fiber diameter of the first fibrous conductive member is 1 μm to 1 μm, or 1, which is within the claimed range of 0.5 to 2.0.
Regarding claim 15,
Yoshida in view of Mizuno teaches the membrane-electrode assembly according to claim 12 (see rejection of claim 12 above), wherein the first fibrous conductive member and the second fibrous conductive member include a same kind of material (see [0016], wherein the first fibrous conductive member and the second fibrous conductive member both contain carbon fiber; see [0028-0035] which describes how a carbon fiber material produced by a specific VGCF method has advantageous properties, wherein “same kind of material” is interpreted in light of [0015] of the specification to mean sharing substantially materials through substantially the same production processes).
Regarding claim 16,
Yoshida in view of Mizuno teaches the membrane-electrode assembly according to claim 12 (see rejection of claim 12 above), wherein the content K2 of the second fibrous conductive member in the second conductive material is 60 mass % or more (see [0018], “and the vapor grown carbon fiber content is 1 to 95% by mass of the whole layer”). In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. (See MPEP 2144.05 I.)
Regarding claim 17,
Yoshida in view of Mizuno teaches the membrane-electrode assembly according to claim 12 (see rejection of claim 12 above), wherein the one of the catalyst layers constitutes a cathode of the fuel cell ([0004], “cathode catalyst layer”).
Regarding claim 18,
Yoshida in view of Mizuno teaches the membrane-electrode assembly according to claim 17 (see rejection of claim 17 above), wherein the other one of the pair of catalyst layers contains catalyst particles B (wherein both the anode and cathode catalyst layers contain catalyst particles [0017] on both sides such that each side has catalyst particles A and B respectively) and a third conductive material, the third conductive material includes a third particulate conductive member and a third fibrous member (see [0016], wherein “on both sides…the catalyst layer contains conductive powder particles… and fibrous carbon” accounts for both the first and third particulate conductive member and fibrous member respectively).
Regarding claim 19,
Yoshida in view of Mizuno teaches the membrane-electrode assembly according to claim 18 (see rejection of claim 1 above), wherein a ratio K3/K1 of a content K3 by mass of the third fibrous conductive member in the third conductive material to the content K1 is in a range of 0.5 < K3/K1 < 2.0 (see [0016] and [0034], wherein Yoshida teaches both catalyst layers on either side to have the same mass composition range, such that K3/K1=1, within the claimed range).
Regarding claim 20,
Yoshida in view of Mizuno teaches the membrane-electrode assembly according to claim 18 (see rejection of claim 18 above), the content K2 ([0018], “and the vapor grown carbon fiber content is 1 to 95% by mass of the whole layer”), the content K3 (see [0044] which describes mixing .1 to 30% by mass of fibrous carbon with the catalyst), which overlaps and thus obviates the claimed range that the content K2 is larger than a content K3 by mass of the third fibrous conductive member in the third conductive material. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. (See MPEP 2144.05 I.)
Regarding claim 21,
Yoshida in view of Mizuno teaches the membrane-electrode assembly according to claim 18, (see rejection of claim 18 above), wherein the gas diffusion layer in contact with the other catalyst layer contains a fourth conductive material, the fourth conductive material includes at least a fourth fibrous conductive member (see [0016] “both sides…gas diffusion layer has a layer containing… a fibrous carbon”, wherein carbon is a conductive material, and wherein the carbon fiber on the other side accounts for the fourth conductive material), and a content K4 by mass of the fourth fibrous conductive member in the fourth conductive material (wherein K4=K2 as Yoshida teaches the same range of carbon fiber for both sides, see rejection of claim 12 and 20 above) is larger than a content K3 by mass of the third fibrous conductive member in the third conductive material (wherein K2>K3, see rejection of claim 20 above, and K4=K2, such that K4>K3).
Regarding claim 23,
Yoshida in view of Mizuno teaches a fuel cell [0001], comprising the membrane-electrode assembly of claim 12 (see rejection of claim 12 above).
Regarding claim 24,
Yoshida in view of Mizuno teaches the membrane-electrode assembly according to claim 12 (see rejection of claim 12 above), wherein a diameter of each of the first fibrous conductive member and the second fibrous conductive member is 300 nm or less, but fails to teach a diameter of 200 nm or less. However, "[A] prior art reference that discloses a range encompassing a somewhat narrower claimed range is sufficient to establish a prima facie case of obviousness."
Regarding claim 25,
Yoshida in view of Mizuno teaches the membrane-electrode assembly according to claim 12 (see rejection of claim 12 above), wherein the first fibrous conductive member and the second fibrous conductive member each have a hollow portion inside [0038].
Regarding claim 27,
Yoshida in view of Mizuno teaches the membrane-electrode assembly according to claim 12 (see rejection of claim 12 above), wherein the catalyst layer containing the first conductive material constitutes a cathode ([0086], “carbon particles…cathode”).
Regarding claim 28,
Yoshida in view of Mizuno teaches the membrane-electrode assembly according to claim 12 (see rejection of claim 12 above), wherein a length of each of the first fibrous conductive member and the second fibrous conductive member is 50 μm or less ([0062], “fiber length of 50 μm or less”) but fails to teach 0.2 μm or more and 20 μm or less. However, [0062] discloses the relationship of how decreasing the fiber diameter is preferably associated with a decreased fiber length, wherein a diameter of 500 nm or less has a preferred length of 100 μm, but a diameter of 300 nm or less has the preferred length of 50 μm or less. Therefore, Yoshida teaches that maintaining a similar proportion of fiber diameter to length can be considered a result effective variable for achieving preferred fiber properties when working with various fiber sizes. Accordingly, it would be expected by one of ordinary skill in the art that a fiber diameter of 150 nm, as seen in [0068-0070] of the instant specification, would be associated with a preferred length of 20 μm or less. Thus, it would be obvious to one of ordinary skill in the art before the effective filing date of the present invention to select a length of each of the first fibrous conductive member and the second fibrous conductive member is 0.2 μm or more and 20 μm or less.
Regarding claim 30,
Yoshida in view of Mizuno teaches the membrane-electrode assembly according to claim 12 (see rejection of claim 12 above), wherein the gas diffusion layer (see rejection of claim 12 above) in contact with the one of the catalyst layers (see rejection of claim 1 above) has no carbon cloth as the substrate layer (see rejection of claim 12 above, wherein the combination results in a GDL with no substrate layer).
Claim 22 is rejected under 35 U.S.C. 103 as being unpatentable over Yoshida (JP5269919B2) in view of Mizuno (JP3503193B2) and Schweiss (US2017222241A1) (refer to enclosed translations for citations).
Regarding claim 22,
Yoshida in view of Mizuno teaches the membrane-electrode assembly according to claim 18 (see rejection of claim 18 above), wherein the gas diffusion layer in contact with the other catalyst layer contains a fourth conductive material (see [0016] “both sides…gas diffusion layer has a layer containing… a fibrous carbon”, wherein carbon is a conductive material, and wherein the carbon fiber on the other side accounts for the fourth conductive material), but fails to teach a content K4 by mass of the fourth fibrous conductive member in the fourth conductive material is smaller than the content K2. Schweiss, analogous in the art of membrane-electrode assemblies, teaches wherein both gas diffusion layers contain carbon fiber (Schweiss, [0036-0037]), and wherein the anodic gas diffusion layer carbon fiber (Schweiss, [0036-0037]) and the cathodic gas diffusion layer carbon fiber (Schweiss, [0036-0037]) are different materials with different densities (Schweiss, [0036-0037]) for improved water management (Schweiss, [0027]). Therefore, it would be obvious to one of ordinary skill in the art before the effective filing date of the present invention to vary the materials of the gas diffusion layer on both sides, as suggested by Schweiss, in order to improve water management (Schweiss, [0027]). Accordingly, Yoshida in view of Schweiss teaches wherein the fourth conductive material has a content K4 by mass of the fourth fibrous conductive member in the fourth conductive material is smaller than the content K2. Additionally, the combination is further obvious as the membrane-electrode assembly of Schweiss contains an analogous structure, including a membrane electrode (25) with catalyst layers (20, 30) and gas diffusion layers on both sides (Schweiss, [0028], see Figure 1).
Claim 29 is rejected under 35 U.S.C. 103 as being unpatentable over Yoshida (JP5269919B2) in view of Mizuno (JP3503193B2) and Takeshi (US-20170373329-A1) (refer to enclosed translations for citations).
Regarding claim 29,
Yoshida in view of Mizuno teaches the membrane-electrode assembly according to claim 12 (see rejection of claim 12 above), wherein the gas diffusion layer in contact with the one of the catalyst layers contains: 35 to 80% by mass of the second fibrous conductive member; 5 to 35% by mass of a second particulate conductive member ([0018], [0086] wherein the mass ratio of particles to fibrous carbon 2:8 and the resin is 40% by mass, such this would result in a layer with approximately 48% by mass fibrous carbon and that the mass of a second particular conductive member is approximately 12%) and 10 to 40% by mass of a polymer resin ([0086], “40%”). However, Yoshida in view of Mizuno fails to teach wherein at least part of the polymer resin is fibrillated. Takeshi teaches wherein at least part of the polymer resin ([0054], “gas diffusion layer… fibrillated thermoplastic resin”) is fibrillated ([0054], “gas diffusion layer… fibrillated thermoplastic resin”). It would be obvious to one of ordinary skill in the art before the effective filing date of the present invention to fibrillate the resin of Yoshida, as suggested by Takeshi, in order to better connect the conductive particles to each other (Takeshi; [0054]).
Response to Arguments
Applicant’s arguments, see “Remarks, filed 10/09/2025, have been fully considered and, due to the amendments, are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Takeshi (US-20170373329-A1).
Applicant argues that combination with Mizuno’s method would not work as peeling would not likely occur at the interface due to Yoshida’s diffusion layer having more voids than that of Mizuno. However, this is not persuasive, as applicant’s arguments are not commensurate in scope with the claims, wherein peeling or the absence thereof is not claimed, neither are voids. Further, Mizuno is silent to any mention regarding voids or number of voids, such that the assertion that Mizuno has less voids is not supported.
Similarly, applicant argues that the peeling strength of Yoshida’s layer is weak such that combination with Mizuno would not result in a reasonable expectation of success. However, this is not persuasive for similar reasons to above, the arguments are not commensurate in scope with the claims, which do not recite a peel strength. Further, Yoshida is silent to the mention of any peeling strength, such that an assertion that Yoshida’s layer is not strong enough for the combination is not supported.
In either case, one of ordinary skill in the art would be expected capable of handling design considerations like peeling strength and void number when combining Yoshida with Mizuno, such that, absent explicit evidence to the contrary, one of ordinary skill in the art should have a reasonable expectation of success.
In response to applicant's argument that that the combination of claim 22 uses Schweiss, which requires a carbon fiber substrate as an essential component, and one of ordinary skill in the art would not conceive of extracting the microporous layer alone, the test for obviousness is not whether the features of a secondary reference may be bodily incorporated into the structure of the primary reference; nor is it that the claimed invention must be expressly suggested in any one or all of the references. Rather, the test is what the combined teachings of the references would have suggested to those of ordinary skill in the art. In the instant case, the combination with Schweiss relies on the teaching that the anodic and cathode gas diffusion layers contain different materials with different densities, wherein incorporating the teachings of Schweiss only requires adapting the materials of Yoshida to the specific side of the battery they are on.
Applicant’s arguments regarding claim 29 are now considered moot in light of the updated rejection with Takeshi (see rejection of claim 29 above).
Applicant argues that claim 1 and all other claims should be allowable based of an allowable independent claim. However, this is not persuasive, as claim 1 has been withdrawn and the rejections on all claims have been sustained.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/PAUL CHRISTIAN ST WYROUGH/Examiner, Art Unit 1728
/TIFFANY LEGETTE/Supervisory Patent Examiner, Art Unit 1723